2006 Fiscal Year Final Research Report Summary
Probing the origin of peculiar dust with high far-infrared emissivity
| Project/Area Number |
17540214
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Astronomy
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| Research Institution | Tokyo Gakugei University |
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Principal Investigator |
DOBASHI Kazuhito Tokyo Gakugei University, Faculty of Education, Associate Professor, 教育学部, 助教授 (20237176)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIURA Shingo Tokyo Gakugei University, Faculty of Education, Research Associate, 教育学部, 助手 (50372454)
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| Project Period (FY) |
2005 – 2006
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| Keywords | dark clouds / interstellar dust / infrared astronomy / interstellar gas / radio astronomy |
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| Research Abstract |
Comparing the visual extinction map of Av measured directly in the optical wavelengths using the data base Digitized Sky Survey I and that derived from the far-infrared dust emission, we found that the dark clouds in the Galaxy are surrounded by dust whose emissivity in the far-infrared wavelengths (>100 micron) is a few times higher than normal dust grains. Such unusual dust seems to be very abundant in the Galaxy, being ubiquitous all over the galactic plain. Purpose of the present study is to probe into the origin such peculiar dust by measuring their reddening curves in the optical and near-infrared wavelengths as well as by probing into the density and temperature of molecular gas in the clouds which may influence on the dust property inside of the clouds.
During the first year of the research period (2005), we concentrated on the development of the 60cm-diameter telescope with other radio astronomical groups in Japan in order to carry out radio observations toward several dark clouds including L1251, IC5146, and rho-0ph. In the second year (2006), we actually performed the ^<12>CO and ^<13>CO (J=2-1) observations with a moderate angular resolution of 10'. In order to probe into the dust distribution and the possible change in the dust properties in the clouds, we also produced maps of color excess E(J-H) and E(H-K) using the database 2 Micron All Sky Survey (2MASS). Comparing all of these dataset, we conclude that the peculiar dust observed inside of the clouds is probably big grain growing inside of the dense cores. On the other hands, dust with high far-infrared emissivity observed in the diffuse boundary of the clouds is likely to be fluffy aggregates, although their definite origin still remains as an open question.
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